The invention relates to a parking brake for a vehicle, comprising a brake actuation lever which is arranged in a jointed manner on a lever holder; a coupling unit which tensions a brake cable during the displacement of the brake actuation lever; a locking device, in order to hold the brake actuation lever in a locking position; and a deflection lever which is articulated pivotably on the lever holder and which is connected in a jointed manner to the brake actuation lever and has the coupling unit for the brake cable.
Parking brakes, in particular foot-operated parking brakes for motor vehicles, are known from practice, which, when a brake actuation lever designed, for example, with a pedal is actuated, exert a corresponding pull on a brake cable pulling on the brake shoes of the parking brake, the latter being tensioned thereby. One disadvantage of these parking brakes is that the lever arm of the pedal, on the one hand, and the distance of the articulation of the brake cable from the body-fixed articulation point of the brake actuation lever, on the other hand, defines unfavorable lever ratios (about 1 to 2), so that, in practice, tension members which bring about a step-up of about four times the pull exerted on them have to be installed between a first and a second part of the brake cable. Such tension members present problems, because, as a rule, the adjustment of the brake cable because of the wear of the brake linings is possible only on one part of the brake cable and the adjustment can therefore be compensated only inadequately. Moreover, these parts make it difficult to install the brake cable, because the latter can be led only at a distance from these and therefore mounting becomes more costly. In addition, such a tension member always constitutes the weak point for material faults and mounting errors.
DE-A-28 05 192 shows a manually actuable parking brake, in which a brake actuation lever is arranged about a pivot axis on a lever holder, furthermore, an intermediate lever being arranged in a jointed manner on the brake actuation lever, the other end of the intermediate link being coupled in an articulated manner to one corner of an essentially triangular deflection lever which is articulated on the lever holder in a further corner and in a third corner provides the possibility of coupling for a brake linkage. A pawl arranged on the brake actuation lever makes it possible to lock the parking brake due to cooperation with a stationary circumferential toothing of the lever holder. The known parking brake has the disadvantage that it requires a relatively large construction space, since the pivoting circle of the link connection point between the intermediate link and the deflection lever has to pivot past the articulation of the brake actuation lever, and, furthermore, the articulations and the deflection lever and the brake actuation lever have to be provided next to one another on the same lever holder. Moreover, the materials of the various levers are also protected, in the region of their articulation, against momentums which arise due to the one-sided lateral mounting of the respectively pivotable part, so that the articulation points and the pin materials must be produced with the appropriate strengths, since they are mounted only on one side. However, The present design of the intermediate lever and deflection lever does not allow mounting on both sides.
DE-A-196 25 804 describes a parking brake, in which a brake actuation lever is pivotably arranged at an articulation point on a lever holder, a bearing point for jointed connection to a deflection lever being provided. The deflection lever has an essentially triangular configuration, in the first corner of which the bearing point is provided and in the second corner of which the cable outlet is arranged. The third corner of the deflection lever is designed as a bearing point for a roller which can be tracked along a lever-holder profile having an indentation. As a result of this rolling, the actuation resistance of the parking brake is increased and, moreover, a favorable transmission ratio is not defined. The parts of the parking brake are arranged on one side of the lever holder.